Molecular and hormonal mechanisms in the final maturation of the oocyte and ovulation of lambari (Astyanax altiparanae): in vivo and in vitro study

• Grant number: 23/16571-9
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2024
• End date: March 31, 2026
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Aquaculture
• Principal Investigator: Sergio Ricardo Batlouni
• Grantee: Sergio Ricardo Batlouni
• Host Institution: Centro de Aquicultura (CAUNESP). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Associated researchers: Laíza Maria de Jesus Silva

Abstract

The consecutive drop in the last five years of ~5% per year in the aquaculture production of native tropical species (~30% of national aquaculture production) is associated, among other reasons, with the unpredictability in the success of the production of young forms. The lambari is an excellent model for this theme because its small size and a short production cycle, in addition to the market's rise and expansion, especially for bait. Our objective is therefore to investigate and fill a historical gap on the molecular and hormonal mechanisms that control final maturation and ovulation with a focus on inducing hormone receptors. We also aimed to study the spatiotemporal expression of LH, progesterone and prostaglandin receptors in vivo and in vitro; and based on this, adjust and propose an even more efficient hormonal induction protocol for this and other migratory species; using in vitro tools for this purpose in native species in an unprecedented way. To this end, consecutive experiments will be conducted with protocols adjusted for the species and recently published (Roza de Abreu et al., 2021 and 2022), now adding the crude lambari pituitary extract for hormonal induction (patent deposited by us in 2021: BR10202101833). In these experiments, with different protocols, samples will be taken at different times for blood collection to analyze the plasma hormonal profile; gonads, for RT-qPCR, histology, immunohistochemistry and in situ hybridization (RNAscope); and pituitary, for analysis of lhb gene expression. We intend to advance the understanding of the reasons for spawning failures by now launching a new focus on the receptors of injected hormones. (AU)